The other day we noted that the US had encountered signs gleaned from wastewater samples taken across the country that COVID cases might be on the rise after weeks of steady declines that recently prompted authorities to start dialing back pandemic-era requirements. But China and the US aren’t the only places where case numbers have started to rise. A surge in coronavirus infections in western Europe has experts and health authorities on alert for another wave of the pandemic in the US even as most of the country has done away with restrictions after a sharp decline in cases. Experts...